The following disclosure relates generally to communications systems and, more particularly, to a self-configuring RF repeater in a telecommunications system.
A telecommunications system may provide communication services to a number of areas called “cells.” Within a cell, a base transceiver station (BTS) may transmit data to a mobile device on a downlink channel using one frequency and receive data from the mobile device on an uplink channel using another frequency. Each mobile device may adjust the power at which it transmits (e.g., the strength of the mobile device's output signal) depending on its distance from the base station.
Certain telecommunications technologies, such as those based on code division multiple access (CDMA), require that mobile devices within a cell adjust their output power such that the signal strength received at the BTS is the same for all the mobile phones being serviced. Accordingly, to keep the signal strength equal at the BTS, mobile devices close to the BTS may use relatively low output power and mobile devices farther away may use an amount of output power that increases with distance. At the edge of the cell, the mobile devices may reach their maximum output power levels.
The increasing demand for high speed data services requires that telecommunications systems provide more bandwidth than may be needed for voice communications. Different ways to provide this bandwidth are available. For example, the power levels of the BTS and mobile devices may be increased. However, this may present health issues. Another way of providing the bandwidth is to bring the mobile devices closer to the BTS so that the existing power can be used in a smaller area. For wide area coverage, this solution may be expensive because it requires that additional cells be added to fill in gaps in the coverage area left by the smaller cells.
Another solution is to add “repeaters” that receive a radio frequency (RF) signal from a BTS and amplify the signal before sending it to a mobile device. A repeater may also amplify the signal from the mobile device before transmitting it to the BTS, enabling the mobile devices to use less power. The amount of amplification or “gain” of the repeater affects the efficiency of the repeater. If the gain is set too low, then the repeater is not covering as much area as possible and so is not being efficient. If the gain is too high, the repeater may generate noise and transmit the noise to the BTS. If the noise reaches a certain level, the noise may overwhelm signals being received by the BTS from other mobile devices not using the repeater, which reduces the effective size of the cell serviced by the BTS.
Accordingly, the gain of a repeater must be set so that it provides effective coverage but does not produce too much noise. Currently, the gain is set for each repeater by a technician. Because repeaters are used primarily for specialized applications, this is not difficult. However, due in part to the need for higher bandwidth in telecommunications systems, it may become expensive and time-consuming to manually optimize the gain of each repeater as repeaters are being deployed in far greater numbers.
Therefore, what is needed is a system and method for automatically setting the gain of an RF repeater in a telecommunications network.